I get asked this an insane amount of times, so I figured I should make a tutorial because it’s ridiculous easy, but people always assume it’s a special method. It’s not; it’s just copy/paste!
STEP 1: When you see a post whose tags you would like to reblog, highlight them and copy them using Ctrl+C
If you have xkit or wrap tag userscript, you copy the tags directly from the dashboard. If not, you can go to their page and copy their tags! I’m using one of my meta tag posts as an example.
STEP 2: Click reblog and paste the tags in the comments section
Don’t worry about formatting that was copied over. Tumblr will automatically strip all colouring and font changes when you click submit.
STEP 3: Erase the unnecessary tags
Some tags are not part of the special tags that you want to copy; some tags are just there for the tag writer to be able to file their posts. Thus, it’s better if you delete them. Since these are my tags, I had added “meta” at the end so I could find this most later if I needed (such as now!). When you copy over the tags, you’re better off deleting tags such as #meta, #otp, #doctor who, #david tennant, etc. Of course, you don’t have to do this, but it is just cleaner.
STEP 4: Add credit
Tags are forms of expression, just like fics, gifsets and photosets. Just because it’s in a tag section doesn’t mean the author shouldn’t get credit for writing it! I always credit long meta tags, because a lot of work went into them. Tumblr etiquette! If it’s a quick or funny tag that’s clearly a joke or something, then crediting isn’t always necessary. But if it’s long meta tags or tag fics, then you should credit! Everyone has their own way, but I write it as (via ______) and then I write the author’s name and link back to them. This post (because it’s mine) would be properly credited as (via winterinthetardis). If you prefer, you can even credit it more simply/cleanly by just linking to the author using a (x), such as (x).
STEP 5: Click Submit!
You’re done :D